Marconi? He gets the most press. My friend Raymond Minichiello, P.E., founder of Guglielmo Marconi Foundation U.S.A. and curator of the U.S. Marconi Museum (www.marconiusa.org), may cringe if I put it that casually. Marconi won patents and made radio a commercial success. Commercial success does a great deal to multiply the use and applications of a technology.
Tesla? In 1943, the U.S. Supreme Court ruled that Marconi's patents were invalid due to Tesla's prior descriptions. Marconi was already gone; Tesla died the same year.
Popov? The U.S. Navy weighed in, giving some credit to Popov (sometimes spelled Popoff) in a 1963 U.S. government publication, History of Communications - Electronics in the United States Navy.
"Popoff utilized his equipment to obtain information for a study of atmospheric electricity… On 7 May 1895, in a lecture before the Russian Physicist Society of St. Petersburg, he stated he had transmitted and received signals at an intervening distance of 600 yards," the Navy's account reads.
In the same year, Marconi transmitted and received signals within the limits of his father's estate at Bologna, Italy.
"Marconi can scarcely be called an inventor. His contribution was more in the fields of applied research and engineering development. He possessed a very practical business acumen, and he was not hampered by the same driving urge to do fundamental research, which had caused Lodge and Popoff to procrastinate in the development of a commercial radio system," the Navy wrote.
Lodge? A professor at Liverpool University, Lodge was experimenting with wireless telegraphy as early as 1888. His system was patented in 1897,
including his coherer receiving detector. Marconi purchased the patent in 1911.
Hertz? In 1888, Hertz appears to have been the first to demonstrate experimentally the production and detection of the waves predicted by Maxwell.
The German physicist made his demonstration in a classroom at Karlsruhe Polytechnic in Berlin.
Fessenden? He is known for early voice and music transmissions. The most famous of his early "broadcasts" was made in 1906 from a station in Brant Rock, MA. Ship radio operators heard it for hundreds of miles at sea. I've also read descriptions of Fessenden's voice and music transmissions as early as the mid-1890s to people on pleasure boats in the St. Lawrence River.
Dolbear? The physics professor from Tufts University won a patent in 1885 for a wireless telegraphy system so similar to Marconi's that he was able to block the Marconi Company from operating in the United States. Marconi later purchased Dolbear's patent.
Loomis? From 1858 to his death in 1886, the dentist Mahlon Loomis experimented with wireless telegraphy mostly using kite-supported wires and a galvanometer that would register changes in current flow in a second wire when the ground connection of the first was interrupted. He was granted a patent in 1873 for the invention of his system.
Stubblefield? The Kentucky farmer and sometimes telephone repairman demonstrated wireless telephony as early as 1892, but to only one man, and in 1902 to a group.
Maxwell? I like to list him in part because, although he didn't configure equipment to demonstrate radio, his brilliant equations described electromagnetism and the propagation of electromagnetic waves.
Some of the early wireless communications demonstrations used the phenomenon of induction. The principles of radio waves and induction have some similarity. Those who differentiate between radio and other forms of "electric" wireless communications cite the differences.
No one invented radio. Radio is a natural phenomenon whose existence can be predicted, as did Maxwell, and whose existence can be observed, as did Hertz. Putting it that way, radio can be "discovered" but not "invented."
When it comes to the inventors, what they did was configure equipment to put radio to use. Who was the first to do that? The answer depends on what "use" you choose to measure. Hertz invented a way to demonstrate the existence of radio waves and to send them across a room. Loomis, Stubblefield, Fessenden, Lodge and others found ways to configure equipment for other various purposes.
Marconi demonstrated applications for radio communications, and then he found a way to sell equipment and services. He patented equipment. No small feat, but did he "invent radio?" Not the way I look at it. Radio was already there.
Ah, but what about the patents?
Footnote by webmaster:
There is a new contender for the inventor of radio, Spaniard Julio Cervera Baviera, according to professor Ángel Faus!